Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Node constructor methods are supposed to be called in syscall
context always. Convert nodes to consistently use M_WAITOK flag
for memory allocation.

Reviewed by: julian

- Account all node stats at the shape mode.
- Do not check destination hook presence, it will be done by netgraph.
- Use u_int instead of int in some places to simplify type conversions.
- Use NG_SEND_DATA_ONLY() macro instead of selfmade equivalent.

Switch from timeval to bintime, to use 1/(2^20) of seconds instead of
microseconds. It allows to use bit shifts instead of some heavy 64bit
mul/div math operations.

Add option to set packets per second limits instead of default
bits per second ones.

Add missing ng_uncallout() on node shutdown.

Approved by: glebius (mentor)

Fix small copy/paste mistake.

Style cleanup.

Approved by: glebius (mentor)

A node that implements various traffic shaping and rate limiting algorithms.

Approved by: glebius (mentor)